Combustor

Abstract

A gas turbine engine combustor is provided with a semi-spherical upstream wall constituted by two correspondingly shaped skins which are spaced apart by pedestals attached to one of the skins to define a space between them. Cooling air is progressively metered into to space through apertures in the first upstream skin to provide effective cooling of the second downstream skin. The cooling air is exhausted from the space through an outlet defined by the first skin and the periphery of the second skin to provide film coating of the upstream end of the combustor side wall.

We claim: 
     
       1. A combustor suitable for a gas turbine engine comprising a wall defining at least the majority of the upstream end of said combustor, said wall comprising first and second generally correspondingly shaped skins which skins are each of generally semi-spherical configuration and a plurality of pedestals attached to one of said skins and abutting the other said skins to maintain said skins in spaced apart relationship whereby a space is defined therebetween, the first of said skins being operationally exposed to a source of pressurised cooling fluid, and the second of said skins defining a portion of the interior surface of said combustor, said pedestals assisting in the conduction of heat from the second skin, said first skin having a plurality of apertures therein for permitting the flow of said pressurised cooling fluid into said space defined between said skins, the apertures in the first outer skin progressively decreasing in size the further they are spaced apart from the combustor center line so as to provide a progressive metering of cooling fluid into said space defined between said first and second skins, said second skin being substantially continuous and having a periphery which co-operates with said first skin to define an outlet for the egress of said cooling fluid from said space between said skins into the interior of said combustor, each of said first and second skins being provided with an additional aperture at its central region and an axially extending sleeve around its corresponding aperture, the sleeve of said second skin locating within and being supported by the sleeve of said first skin. 
     
     
       2. A combustor as claimed in claim 1 wherein said pedestals are attached to said second skin. 
     
     
       3. A combustor as claimed in claim 1 wherein said combustor is provided with a side wall and said first skin is integral with said side wall. 
     
     
       4. A combustor as claimed in claim 1 wherein said sleeves extend in an upstream direction. 
     
     
       5. A combustor as claimed in claim 1 wherein said sleeve attached to the said second skin carries a plurality of swirler vanes. 
     
     
       6. A combustor as claimed in claim 1 wherein said outlet for the egress of cooling air is located adjacent the side wall of said combustor so as to provide film cooling thereof. 
     
     
       7. A combustor as claimed in claim 1 wherein said cooling fluid is air.